I have an FNP 40 USG (combo safety/decocker). I have fired 1083 rounds through it...a box of Blazer Aluminum 165gr. a box of Magtech 180gr. and 3.5 boxes of Remington UMC 180gr. and then 800 rounds of reloads using 5 gr. of W231 and 180gr. Berry's plated 180GR RN bullets. In 1083 rounds, I had one stoppage, and that was due to a reload with a crooked bullet, that still chambered, but wouldn't go into battery.
Yes, mine did get the ding on the slide from the slide stop, but it was as bad as it got after the first day firing it. The only time in about 80 magazines fired that it did not lock the slide back was the very first time.